In a known manner, a power supply is able to be connected to an external power supply and also in a known manner, an external consumer, e.g. a motor, is able to be connected to the drive or to its switching element. With the drive or its switching element an operating voltage generated by the power supply of the switchgear is able to be supplied via an outgoing operating voltage line from the power supply to the consumer via the switching element. The respective consumer is then supplied with electrical power, i.e. activated, if the switching element is activated.
Switchgear is known per se, being referred to as a motor starter for example. The applicant of an embodiment of the present invention also offers under the designation “SIRIUS compact starter” a switching device also referred to as a universal motor starter, which fulfills the requirements in accordance with IEC/EN 60947-6-2 and combines the functions of a circuit breaker, an electronic overload relay and a contactor as a switching element in one housing and is able to be used wherever standard alternating current motors up to 32 A (appr. 400V) will be started directly. The compact starter is available as a direct or reversing starter.
In an embodiment as reversing starter the compact starter is characterized by the following components: Reversing starter, two removable main conductor terminal blocks, two six-pole removable auxiliary and control conductor terminal blocks, “overload” and “short circuit/malfunction” signal switches and internal auxiliary switches as well as two optional external auxiliary switch blocks (two normally open, two normally closed or one normally open and one normally closed). For locking the direction of rotation there is provision for the contactors of the reversing starter to be locked in relation to one another. This protective precaution prevents the contactors being simultaneously activated for the same direction of rotation and causing a short circuit. The contactors are locked both mechanically against shock stresses and also electrically against incorrect activation.
For mechanical contactor locking there is provision for a reversing gear to block the directions of rotation mechanically against one another. If the main contacts are closed for a first direction of rotation, the reversing gear prevents the simultaneous closing of the main contacts for the other direction of rotation and vice versa. For electrical contactor locking an auxiliary contact embodied as a normally closed contact is provided in the reversing starter for each direction of rotation. The control current of the other respective direction of rotation is looped through these auxiliary contacts. I.e. when the main contacts for the first direction of rotation are closed, the auxiliary contact opens and interrupts the control current circuit of the other direction of rotation and vice versa. This ensures that if a control voltage is present for one direction of rotation, the main contacts for the other direction of rotation will not be switched.